[Chromecast] Add a return value after NOTREACHED in tests.

Required to compile on internal ARM compiler.

BUG=

Review URL: https://codereview.chromium.org/1351493003

Cr-Commit-Position: refs/heads/master@{#349997}

chromecast/media/BUILD.gn

@@ -16,6 +16,7 @@ group("media") {
 
 test("cast_media_unittests") {
   sources = [
+    "audio/cast_audio_output_stream_unittest.cc",
     "cma/backend/audio_video_pipeline_device_unittest.cc",
     "cma/base/balanced_media_task_runner_unittest.cc",
     "cma/base/buffering_controller_unittest.cc",

chromecast/media/audio/BUILD.gn

@@ -26,10 +26,6 @@ source_set("audio") {
 source_set("test_support") {
   testonly = true
 
-  sources = [
-    "cast_audio_output_stream_unittest.cc",
-  ]
-
   configs += [ "//chromecast:config" ]
 
   deps = [

chromecast/media/audio/cast_audio_output_stream_unittest.cc

@@ -80,8 +80,12 @@ class FakeAudioPipelineDevice : public AudioPipelineDevice {
         return kFramePending;
       case PIPELINE_STATUS_ERROR:
         return kFrameFailed;
+      default:
+        NOTREACHED();
     }
-    NOTREACHED();
+
+    // This will never be reached but is necessary for compiler warnings.
+    return kFrameFailed;
   }
   RenderingDelay GetRenderingDelay() const override { return RenderingDelay(); }
   bool GetStatistics(Statistics* stats) const override { return false; }